This invention relates to a self-closing valve-and-lid assembly adapted for closing the open top end of a container fillable with pressurized product. It also refers to a novel lid and valve disc, both of which are suitable for being used in the novel valve-and-lid assembly.
Valve-and-lid assemblies which are used to close the open top end of a can or the like container, especially such container destined to be filled with a preferably liquid product and a pressurizing agent, are well known in the art of aerosol cans and are described in numerous patents and other publications.
For instance, German Offenlegungsschrift No. 27 22 265 of George Bernard Diamond describes a pressurized can which is closed off at the top by a lid, preferably of metal such as aluminium, and which is equipped with a discharge valve mounted in the center of the lid, on a common central axis of the valve-and-lid assembly.
The valve is provided with a product passage, a valve disc or plate having a central opening, and with a valve body which cooperates with the valve disc to obturate the product passage when the valve is in closed position; at least one of the two aforesaid valve elements is usually made of an elastically resilient material.
The lid comprises a centrally located dome part which protrudes, in the shape of an inverted cup or bell, from a main lid plane in which a flat part of the lid surrounding the dome part extends, and which plane extends radially to the above-mentioned central axis. The dome part is provided with a central opening coaxially with that of the valve disc and is crimped or stamped in another suitable manner to hold the peripheral zone of the valve disc in a fast, liquid- and gas-tight manner. The periphery of the lid is sealingly connected with a top rim of the container sidewall surrounding the said container top opening, and extends generally to the said central assembly axis.
The lid including the dome part thereof must usually be rigid under conditions of filling product (and, of course, propellant of such is used) into, and of discharging product (and propellant) from the container.
When opening the valve, the valve disc and valve body are so changed in their position relative to one another that there opens a gap between them which permits the flow of product through the product passage of the valve to the outside.
However, in this known valve and all others that have come to our knowledge, the manufacture of the movable part, i.e. the valve body which carries a valve stem and on the latter often an atomizer head, is relatively complicated, especially when it is to be manufactured by means of modern injection molding techniques. Moreover the known valves often require costly spring means for biassing the valve body into its closing position.
It is another drawback of known valve-and-lid assemblies that insertion of a sleeve or stem part of an atomizer head or of a filling head used for introducing product and/or propellant into the interior of a container leads frequently to damage of parts of the valve, especially the small elastically resilient valve disc or gasket that these valves usually require.